The invention relates to a device to machine workpiece edges having variable dimensions using a device for clamping the workpieces and a machining unit.
It is a known procedure to use spherical vessels with diameters up to 40 meters to transport liquefied gases, for example, liquefied natural gas, on ships. These spherical vessels are made up of individual metal sections which are variable over a large range of sizes, depending on the diameter of the spherical vessel. Aluminum is the material used for these parts, which are, for example, 4 meters wide, 11 meters long and between 0.03 and 0.07 meters thick. In order to prepare for welding, it is necessary to provide the edges of the metal sections with a seam. It is known to prepare a seam, for example, an X-shaped or V-shaped seam, on the curved sections by means of milling, whereby the contour to be milled is optically marked, oriented towards the milling unit and outlined by the milling unit one more time by means of optical sedating. A disadvantageous and time-consuming aspect of this is the necessary marking procedure and the manual repositioning and reclamping of the workpiece.
For this reason, it would be desirable to create a device with a clamping device which avoids prior marking and time-consuming, manual handling.
In order to avoid vibration of the workpiece edges to be milled, they would have to be supported and secured as far to the outside as possible by the clamping device. For this purpose, it would be necessary to make a clamping device specifically adapted to every single workpiece contour, which is not economically feasible and which would call for enormous storage areas for the myriad of clamping devices and also entail lengthy retooling times.
The invention is based on the objective of clamping the workpieces into only one device, regardless of their dimensions and shapes.